simplified shower._isNumber
simplified shower._isNumber()
simplified shower._checkInteractiveElement()
shower.getSlideNumber JSDoc: slideId is String instead of Number
JSDoc: All callbacks are optional
JSDoc: shower.enterListMode return Boolean
JSDOc: shower.scrollToSlide return only Boolean
JSDoc: shower.getSlideHash return String
JSDoc: domElem -> HTMLElement
shower.runSlideshowIfPresented return Boolean
Removed unused arguments
Merge pull request #108 from miripiruni/master

Fixes for JSDoc & Clean-up